Electromagnetic regulating apparatus



June 19, 1934. A. H. CHILTON 1,963,825

ELECTROMAGNETIC REGULATING APPARATUS 7 Filed Aug. 5, 1933 4 Sheets-Sheet 1 June 1-9, 1934. c oN 1,963,825

ELECTROMAGNETIC REGULATING APPARATUS Filed Aug. 5, 1935 4 Sheets-Sheet 2 June 19, 1934. A H, HI T N 7 1,963,855

ELECTROMAGNETIC REGULAT ING APPARATUS Filed Aug. 3, 1933 '4 Sheets-Sheet 3 5 I I Ill/[I 7717/7] June 19, 1934. A H, HI TON 1,963,825

ELECTROMAGNETIC REGULAT ING APPARATUS Filed Aug. 1933 4 Sheets-Sheet 4 Patented June 19,1934 1,963,825

UNITED STATES PATENT OFFICE ELECTROMAGNETIC nnovta'rmc srrxax'rus Alfred Henry Chilton, London, England, assignor to J. Stone & Company Limited, Depti'ord, England, a company of Great Britain Application August 3, 1933, Serial No. 683,558 In Great Britain January 28, 1933 6 Claims. (Cl. I'll-#229) This invention concerns improvements in or Figure 1 is a rear elevation of a carbon pile relating to electro-magnetic regulating appararegulator intended more especially for dynamo tus and is more especially concerned with soregulation purposes in train lighting installacalled carbon pile regulators such as are comtions,

5 monly employed, for example, in lighting instal- Figure 2 a vertical section thereof, 60

lations on railway vehicles. Figure 3 a front elevation of the rotor alone,

In a regulator of this kind, it is necessary that Figure 4 a similar view of an alternative form the electro-magnetic actuating force, the reacof rotor, tion of the carbon pile, and the force of the usual Figure 4a a similar view illustrating modified spring or equivalent loading means should be rotor profiling, balanced over the range of operation of the reg- Figure 5 a front elevation of a carbon pile ulator. As the reaction of the pile, which varegulator intended more especially for lamp voltries according to a given law, is in general a age regulation purposes in train lighting instalrelatively small component, the required balance lations, and

involves the matching of the torque/movement Figure 6 a vertical section thereof. characteristic of the electro-magnetic actuaing Referring first of all to Figures 1-3. the various device against that of the spring or other loadcomponent parts of the regulator are mounted ing means. Thus, if the characteristic of the upon aframe 1. The iron magnet core 2, which electro-magnetic device is of a complex or is of approximately inverted U-shape and car- 0 curved nature, as has hitherto been the case, ries the exciting winding or windings 3 upon its a relatively complicated spring compensation yoke portion, is carried in a forward extension system is required toprovide a characteristic 4 of the frame 1. Supported in ball bearings 5 that can be matched with it. The principal in the main frame 1 and forward extension 4 object of the present invention is to provide a is a spindle 6 carrying an iron rotor 7 located magnet system matched over a wide range with between the opposed pole-faces 8 of the magnet a relatively simple spring system. core. These pole-faces are of a concave substan- With this object in view according to the prestially cylindrical profile (Fig. 1) concentric with ent invention, in electro-magnetic regulating apthe axis 10 of rotation of the rotor. The convex paratus, and particularly a carbon pile regulaend-faces of the rotor 7 (Figures 3 and 4) are protor, in which the pile compression is varied by filed to give a predetermined rising torque/move- 8 a magnet rotor rocking between opposed magnet ment characteristic which is a substantially pole-faces and attracted by the latter against the straight line. The larger leading parts 11 are eilort oi aspring with astraight line rising charprofiled so as to give a tapered air gap when acteristic, the endiaces of the rotor are profiled the rotor is in the attracted position (Fig. 1).

so that the characteristic of the magnet device The trailing parts 13 are differently profiled to is matched as closely as possible with the chargive a predetermined leakage effect, the profiling acteristic of the spring over a wide range, such of such trailing parts having been found to exert profiling extending over those portions of the an important influence upon the resultant charfaces which come within the polar embrace in acteristic. In the particular case illustrated, the the fully attracted position and also over those parts 11 are struck from centres 12 eccentric to portions which remain outside the polar emthe axis 10 of rotation and the parts 13 from said brace. With such a magnet, the spring may act axis of rotation. Each centre 12 is located on without even the necessity for a variable lever that side of the axis 10 which is adjacent the arm. In one appropriate arrangement, theroface-part 11 struck from it and, as illustrated,

tor spindle carries a disc or drum to the rim of somewhat to that side of the longitudinal axis which is attached a flexible metal band. The of the rotor which is remote from said facesaid band, after passing over an arc of the disc part. Consequently, when the rotor is in the at or drum, is connected to a tension spring which tracted position, the air gaps between the poleis thus extended proportionately to the rotor faces and the parts 11 of the end-faces of the movement, thereby giving the straight line risrotor taper from the leading tips 14 of the rotor ing characteristic. towards the trailing tips. Wlth such profiling,

Two embodiments of the invention will now the magnet possesses a substantially straight line he described by way of example with reference to rising characteristic. The straight line char- 66 the accompanying drawings, in which:-- acteristic can be modified by varying the profiling of the face-parts 11, 13. In Figure 4a a series of different profiles oi the face-parts 11, 13 is indicated by dottedlines and it is possible by combinations of such profiles to obtain a variety of straight line characteristics. The shape of the body of the rotor may be modified to meet requirements. In Figures 1-3, the rotor, which is rectangular in cross section, is tapered somewhat from the middle towards the ends, and toe pieces 15 are formed thereon at the leading tips. In Figure 4, the rotor-is of the shape of an elongated rectangular prism.

An overhanging extension of the spindle 6 on the rear side of the frame 1 carries a disc 16 and a crank 17. The latter is connected by a crank-pin 18 to a push rod 19 carrying a compression plate 20. The pile 21 of thin carbon discs is arranged between the plate 20 and a top plate 22 having an upward extension 23 which is connected by a pivot "24 to a bracket 25. This bracket is mounted upon the top of the frame 1 in a vertically adjustable manner by means of a screw 26 with a grooved head 27 engaged by the forked end of said bracket and is locked in position by means of a screw 28 passing through a slot 29 in said bracket. Insulated pins 30, dependent from the plate 22 and carrying a plate 31 through a hole in which the rod 19 freely passes, constitute a cage in which the pile is guided with a slight degree of freedom. A vertically disposed helical tension spring 32 is connected between a metal tape 33, which after passing around a part of the periphery of the disc 16 is anchored thereto at 34, and an adjustable attachment means 35 which is substantially identical with that 25--2'7 for the pile. The disc 16 also carries a crank-pin 36, which is connected with a dash-pot 37, a counter-weight 38 and a stop 39 whose movement is limited by two adjustable screw abutments 40.

Since the spring 32 will be extended proportionately to the rotor movement, the simple spring system shown will have a substantially straight line rising torque characteristic which matches that oi. the magnet over the wide range of movement permitted by the stop-abutments 40. The adjustable attachment means 2629 and 35 permit of adjustment of the initial compression and tension respectively in the carbon pile and spring. The manner of operation of such a regulator is well known and need be only briefly referred to: With increasing excitation of the magnet winding or windings 3, connected for example, across the dynamo to be regulated, the rotor 7 tends to be attracted from its initial position (see the position of the leading tips as indicated by achain line in Figure 1) towards the final position illustrated in Figure 1, this movement being resisted by the spring 32. The

1 said rotor movement. translated through the crank 19 and plate 20 results in the decompression 01' thecarbon pile 21. The resultant increase of the resistance is utilized for regulation purposes by, for instance, disposing the carbon pile in serieswith the field windings of the dynamo to be regulated. The dash-pot 3'1 counter-acts any tendency towards jerking or hunting action of the regulator.

As regards the magnet and spring systems, the lamp voltage regulator illustrated in Figures 5 and 6 is essentially similar to that previously described. The disposition of the carbon piles and the means for their control are, however, different. In the present example, the carbon piles 41, of which two, three or more are provided to carry the lamp current, are mounted above the magnet system upon a separate platform 42 secured to the frame 1. In place of the push rod 19 of Figures 1 and 2, use is made of a push rod 43 connected by a see-saw lever 44 to a pull-rod 45 around which the piles 41 are grouped. This pull-rod 45 incorporates a length-adjustment device which takes the form of a turnbuckle 46 but is designed to give a finer adjustment than an ordinary turnbuckle. The turnbuckle 46 has at the two ends threads of the same sense but of somewhat diflerent pitch. Such a device provides a very fine adjustment as the eifect of the two threads is diiierential, i. e. for one turn of the device, the length adjustment is equivalent only to the difierence between the pitches of the two threads. The pull rod 45 acts upon the carbon piles 41 through an equalizing spider 47 (a beam if two piles are'usedi having a part spherical socket 48 engaged by a part-spherical head 49. on the rod 45.

The carbon piles 41, when in use, experience a considerable rise of temperature with attendant expansion which, unless compensated for, may seriously derange the precision of the regulator. According to a further feature of the invention, a compensating device for this purpose comprises a ring 50 of a material which expands with rise of temperature, a number of spokes 51 of a material 'with a relatively low or negligible thermal expansion, such as mild steel or nickel-steel alloy and a hub 52, the spokes being arranged at an angle of inclination to the plane of the ring. This device is shown interposed between each carbon pile and the equalizing spider 47. The ring 50 which is of a material, for example aluminium, of good conductivity and not too large heat capacity so as to respond readily to temperature changes in the pile, is mounted upon the pile with the interposition of the usual metal contact 116 piece and an insulating disc or washer. The hub 52 is connected pivotally with the spider 47, said hub being extended upwardly and the extension divided by a diametrical slot, whilst holes for a pivot pin 53 are drilled at right angles to the slot. The effect of this compensating device is as follows: The ring 50 will follow the temperature rise of the carbon pile 41 and will expand in diameter. The spokes 51 on the other hand, will expand little or not at all so that their incll- 1 nation will decrease, causing a decrease in the depth 0! the device between the hub 52 and ring 50. The size of the ring and initial inclination of the spokes is designed so that the decrease in depth of the compensating device substantially counterbalances the increase in length of the carbon pile itself over a sumcient range of temperature variation. In order to permit of the variation of the inclination of the spokes 61, these may be made of relatively flexible wire, a suflicient number of spokes being provided to take the maximum pressure exerted on the pile.

The manner of operation of such a lamp voltage regulator is well known and requires no detailed description here.-- The most usual arrangement is that the magnet winding 3 is subject to the lamp voltage whilst the carbon piles 41 constitute a resistance in series with the lamp load. The separatepiles are connected in parallel with each other. Upon the lamp voltage tending torise, the regulator'acte to relieve the pressure upon the piles and thus to increase their resisti themselves constant. The initial setting of the 1 .teristic, and a magnet system consisting oi, a

magnet with opposed pole-laces and a rotor mounted to rockqbetween said pole-faces and acting, under the attraction thereof, upon said controlled element in opposition to said spring, the end-races of said rotor being profiled so that the characteristic of the magnet system is matched as closely as possible with the characteristic of the spring over a wide range, such profiling extending over those portions 0! the faces which come within the polar embrace in the fully attracted position and also over those portions which remain outside the polar embrace.

2. Carbon pile'regulator. comprising a carbon pile, a magnet system consisting of a magnet with opposed pole-faces and a rotor mounted to rock between said pole-faces and operative when attracted thereby for varying the compression of said carbon pile, and a spring system operative upon said rotor with a constant leverage in opposition to the magnet attraction, said spring system having a rising straight-line characteristic and the end-faces of said rotor being so profiled that the characteristic oi. the magnet system is matched as closely as possible with the characteristic of the spring system over a wide range, such profiling extending over those portions of the faces which come within the polar embrace in the fully attracted position and also over those portions which remain outside the polar embrace. W

3. Carbon pile regulator, comprising a,carbon pile, a magnet system consisting of a magnet with opposed pole-faces and a rotor 0! rectangular cross-section mounted to rock between said pole-faces and operative when attracted thereby for varying the compression of said carbon pile, and a spring system operative upon said rotor with a constant leverage in opposition to the magnet attraction, said spring system having arising straight-line characteristic and the end-laces of said rotor being so profiled that the characteristic of the magnet system is matched as closely as possible with the characteristic of the spring system over a wide range, such profiling extending over those portions or the races which come within the polar embrace in the fully attracted position and also over those portions which remain outside the polar embrace.

4. Carbon pile regulator, comprising a carbon pile, a magnet system consisting of a magnet with opposed pole-races and a rotor mounted to rock between said pole-faces and operative when attracted thereby for varying the compression 01' said carbon pile, and a spring system opposing the magnet attraction and consisting of a rotatable arcuate part concentric with its axis oi rotation and connected to said rotor, a spring whose force is substantially proportional. to its elongation, a flexible member which is connected at one end to said spring and at the other end is wrapped over and anchored to said arcuate part, the end-laces of the rotor being so profiled that the magnet system has a rising straight-line torque-characteristic which can be readily matched with the characteristic of the spring system over a wide range, such profiling extending over those portions of the faces which come within the polar embrace in the fully attracted position and also over those portions which remain outside the polar embrace.

v 5. Electro-magnetic regulating apparatus, comprising a magnet system with a rotor rockable between opposed pole-faces and having its endlaces profiled so that the magnet s1 stem has a 106 rising straight-line torque-characteristic, a carbon pile, a link constituting an operative connection between said "rotor and carbon pile, and a fine length adjustment device for said link in the form of a differential turnbuckle.

6. Electra-magnetic carbon pile regulator consisting of a carbon pile and a magnet system comprising a magnet and a rotor operatively connected with the carbon pile and mounted to rock between the opposed pole-laces oi' the magnet, the said rotor having its end-faces profiled in such manner as to obtain a rising straight-line torquecharacteristic for said magnet system, the leading parts of said end-laces, which come within the pole-faces in the attracted position of the rotor, being eccentrically profiled so that the air gaps taper from the leading tips of the rotor, and the trailing parts of said end-faces, which remain outside the pole-faces, being substantially concentrically profiled for the purpose set forth. 125

HENRY CHILTON.

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